Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Sign in to follow this  

AR2741 & AR2740, Large Prominence | HA & CaK | May 14th 2019

Recommended Posts


I had a strange day, where I went to work this morning for a little bit fully expecting bad weather per the report. On the way back home, it was suspiciously clear out. I carried on, ran some errands, etc, and it was still suspiciously clear. I just knew, the moment I even thought about taking a look, the clouds would roll in and it would storm. I'm convinced that the weather lords here in Florida definitely have something against my prying eyes into the sky. I tempted fate and went home. I peaked from the observatory, still no clouds. I got everything going and the seeing was just dreadful for my 8" options, I evaluated them a while until I was convinced there was no option to go 8" today. I was going to image at small scale and call it a day, thankful for a fairly clear sky still. Yet, still no clouds! So, I put my old 120mm F8 achromat on the saddle and let it take a look. Seeing supported this aperture nicely, so I figured, let's roll with it and see what happens. AR2741 was beautiful! And the large hedge prominence on the limb was just exploding with detail and was so wispy and full of strands. I grabbed data at two scales, to compare 80mm to 120mm in the same conditions.























Celestron Omni XLT 120mm F8.3 Achromat + Baader UV/IR Block Filter
Quark Chromosphere + 0.5x focal reducer + IMX174 (HA larger scale)

ST80 + Baader UV/IR Block Filter
Quark Chromosphere + IMX174 (HA smaller scale)

ST80 + Baader Blue CCD-IR Block Filter
PST CaK Filter + 2nd ERF + 3x Barlow + IMX174 (CaK)


Very best,

  • Like 9
  • Thanks 1

Share this post

Link to post
Share on other sites

Great result Marty. Clouds are evil beings I swear :grin:

Just out of curiosity which "Baader IR cut filter" do you use in your Ca-K setup? Am wondering if my images might benefit from an IR cut filter.

Share this post

Link to post
Share on other sites


For Calcium & Gband, I use a Baader 2" Blue CCD-IR Block imaging filter.

This one, but in 2" size:


These dielectric Baader anti-ghosting imaging CCD-IR blocked filters are excellent D-ERFs and can easily handle 150mm refractor apertures so long as they are deep into the light cone.

Very best,

  • Thanks 1

Share this post

Link to post
Share on other sites

Excellent images Martin, I guess " Dreadful " seeing in Florida equates to good seeing in the UK :grin:


Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...

Important Information

By using this site, you agree to our Terms of Use.